I love the colours! I've been wanting to try this out for myself for a while, now I actually have the right equipment, I can Were these the colours on the night or did you alter them? (I'd check through the comments but there's a lot of them, so I don't know if this has been asked already or not, sorry if it has!)
Haha, I always find myself using the wrong white balance by mistake. I'll take a photo and then wonder why it's orange or blue...*alters the white balance* Ah there we go, much better! It's because I tend to forget to change it back after I'm done. Great, well I've got a raw converter on my computer now so I'll have to make good use of it I'll post my results up when I've had a go!
Just make sure you do them the same way as the star trails are done, on a tripod with 2-4 seconds exposure only and many shots. I'm going to go try the freeway lights again taking 20 shots in series of the traffic. They are just so many new ideas I have now!